A Chinese radical (Chinese: 部首; pinyin: bùshǒu; literally: "section header") is a graphical component of a Chinese character under which the character is traditionally listed in a Chinese dictionary. This component is often a semantic indicator (that is, an indicator of the meaning of the character), though in some cases the original semantic connection has become obscure owing to changes in character meaning over time. In other cases the radical may be a phonetic component or even an artificially extracted portion of the character.

Radicals are also sometimes called "classifiers", but this name is more commonly applied to grammatical classifiers.

In the earliest Chinese dictionaries, such as the Erya (3rd century BC), characters were grouped together in broad semantic categories. Because the vast majority of characters are phono-semantic compounds, combining a semantic component with a phonetic component, each semantic component tended to recur within a particular section of the dictionary. In the 2nd century AD, the Han dynasty scholar Xu Shen organized his etymological dictionary Shuowen Jiezi by selecting 540 recurring graphic elements he called bù (部 , "categories").[1] Most were common semantic components, but they also included shared graphic elements such as a dot or horizontal stroke. Some were even artificially extracted groups of strokes, termed "glyphs" by Serruys (1984, p. 657), which never had an independent existence other than being listed in Shuowen. Each character was listed under only one element, which is then referred to as the radical for that character. For example, characters containing 女 nǚ "female" or 木 mù "tree, wood" are often grouped together in the sections for those radicals.

Mei Yingzuo's 1615 dictionary Zihui made two further innovations. He reduced the list of radicals to 214, and arranged characters under each radical in increasing order of the number of additional strokes – the "radical-and-stroke-count" method still used in the vast majority of present-day Chinese dictionaries. These innovations were also adopted by the more famous Kangxi Dictionary of 1716. Thus the standard 214 radicals introduced in the Zihui are usually known as the Kangxi radicals. These were first called bùshǒu (部首, literally "section header") in the Kangxi Dictionary.[1] Although there is some variation in such lists – depending primarily on what secondary radicals are also indexed – these canonical 214 radicals of the Kangxi Dictionary still serve as the basis for most modern Chinese dictionaries. Some of the graphically similar radicals are combined in many dictionaries, such as 月 yuè "moon" and the 月 form (⺼) of 肉 ròu, "meat, flesh".

The English term "radical" originated from a mistaken analogy between the structure of characters and inflection of words in European languages.[a] In fact Chinese radicals are usually secondary additions to a character, and not any kind of "root".[3] The term "classifier" is sometimes used instead, though this may lead to confusion with grammatical classifiers (measure words).[4]

Radicals may appear in any position in a character. For example, the radical 女 appears on the left side in the characters 姐, 媽, 她, 好 and 姓, but it appears at the bottom in 妾. However, there are two radicals that have the shape 阝, but are indexed as different radicals depending on where they appear in the character. When used as the abbreviated radical form of 邑 yì "city" (as in 都 dū "metropolis", also read dōu "all") this component appears on the right side of a character, but when used as the abbreviated radical form of 阜 fù "mound, hill" (as in 陸 lù "land") it appears on the left. However, there are regularities in the positioning of radicals within most characters, depending on their function: semantic components tend to appear on the top or on the left side of the character; similarly, phonetic components tend to appear on the right side of the character or at its bottom.[5] These are only loose rules, though, and have exceptions.

Many character components (including those used as radicals) are distorted or change in form in order to fit into a block with other components. They may be narrowed, shortened, or may have different shapes entirely. Changes in shape, rather than simple distortion, may result in a reduction in the number of strokes used to write a component. In some cases, these combining forms may have several variants. The actual shape of the component when it is used in a character can depend on its placement with respect to the other elements in the character.

Some of the most important variant combining forms (besides 邑 → 阝 and 阜 → 阝as discussed above) are:

刀 "knife" → 刂 when placed to the right of other elements:

examples: 分, 召 ~ 刖

counter-example: 切

人 "man" → 亻 on the left:

囚, 仄, 坐 ~ 他

心 "heart" → 忄 on the left:

杺, 您, 恭* ~ 快

(*) 心 occasionally becomes ⺗ when written at the bottom of a character.

Over 80% of Chinese characters are phono-semantic compounds,[6] with a semantic component giving a broad category of meaning and a phonetic component suggesting the sound. Usually the radical is also the semantic component, but this is not always the case.[7] Thus although some authors use the term "radical" for semantic components (義符 yìfú),[b][8] others distinguish the latter as "determinatives"[3] or "significs"[9] or by some other term.[c][d][e]

There are numerous instances of characters listed under radicals which are merely artificial extractions of portions of those characters, and some of these portions are not even actual graphs with an independent existence (e.g., 亅 jué or juě in 了 liǎo), as explained by Serruys (1984), who therefore prefers the term "glyph" extraction rather than graphic extraction (p. 657). This is even truer of modern dictionaries, which reduce the number of radicals to less than half the number in Shuowen, at which point it becomes impossible to have enough radicals to cover semantic elements in every character. In the Far Eastern Chinese English Dictionary for instance, 一 is a mere artificial extraction of a stroke from most of its subentries such as 丁 dīng and 且 qǐe; the same is true of 乙 yǐ in 九 jiǔ; 亅 jué or juě in 了 liǎo, le; 二 èr in 亞 yà and yǎ; 田 tián in 禺 yù; 豕 shǐ in 象 xiàng "elephant", and so on.

There are also instances of radicals which play a phonetic and not a semantic role in characters, such as 臼 jiù "a mortar" in 舅 jiù "maternal uncle" (Shuowen lists this under its semantic component 男 nán, "male", but the 200-odd radicals used in modern dictionaries do not include all the semantic components that are used) and 舊 jiù "owl; old" (listed in the Far East on p. 1141 under the header 臼); 虎 hǔ "tiger" in 虖 hū "shout"; 鬼 guǐ (originally "helmet"[12]), now "ghost", in 魁 kúi, "leader"; 鹿 lù "deer" in 麓 lù, foothills; 麻 má "hemp" in 麼 ma, mó "tiny"; 黃 huáng "yellow" in 黌 hóng "a school"; 羽 yǔ "feather" in 翌 yì "next";[13] 齊 qí in 齎 jī "to present"; 青 qīng in 靖 jìng "peaceful", 靚 jìng "to ornament; quiet"; and 靜 jìng "quiet", and so on. In some cases, arbitrarily chosen radicals coincidentally play a semantic role in the characters listed under them.[7] In general, phonetic components do not determine the exact pronunciation of a character, but only give a clue to a its pronunciation. While some characters take the exact pronunciation of their phonetic component, others take only the initial or final sounds.[14] In fact, some characters' pronunciations may not correspond to the pronunciations of their phonetic parts at all, which is sometimes the case with characters after having undergone simplification.

The 8 characters above all take 也 for their phonetic part, however, as it is readily apparent, none of them take the pronunciation of 也, which is yě. This disparity was caused by simplification in the characters 他 and 她, as their phonetic parts were originally 它 (pinyin: tā). 拖 also was originally written with 它 as its phonetic part, but only took its initial sound. The pronunciations of 池, 驰, 弛, 施, 地 differ from 也 both in initial and final sounds.

The character simplification adopted in the People's Republic of China and elsewhere has modified a number of components, including those used as radicals. This has created a number of new radical forms. For instance, 食shí is written 飠 when it forms a part of other traditional characters, but is written 饣 in simplified characters. The difference between the traditional and simplified version of the same character can therefore lie solely in the visual appearance of the radical. One example is the character for yǔ "language"; the traditional character is 語, whilst in the simplified 语 only the radical is altered. The same characters (or characters with a common ancestor) are used not only in China, but in Japan as well. However, simplification of the older, more complex characters has been done in different ways in these two countries. Chinese simplification of the characters tends to be more liberal, done in an effort to increase literacy by greatly simplifying characters. Conversely, Japanese simplification of the characters has been more conservative, and inherently has created modern characters which more strongly resemble their traditional counterparts.[16]

Most dictionaries use radical classification to index and lookup characters, although many present-day dictionaries supplement it with other methods as well. Following the "section-header-and-stroke-count" method of Mei Yingzuo, characters are listed by their radical and then ordered by the number of strokes needed to write them.

The steps involved in looking up a character are:

Identify the radical under which the character is most likely to have been indexed. If one does not know, then the component on the left side or top is often a good first guess.

Find the section of the dictionary associated with that radical.

Count the number of strokes in the remaining portion of the character.

Find the pages listing characters under that radical that have that number of additional strokes.

Find the appropriate entry or experiment with different choices for steps 1 and 3.

For example, consider the character 信 xìn, meaning "truth", "faith", "sincerity", and "trust". Its radical is 亻 rén "human" (a compressed form of 人) and there are seven additional strokes in the remaining portion (言 yán, "speech"). To look up this character in a dictionary, one finds the radical for "human" in the part of dictionary that indexes radicals. The various radicals will be organized by the number of strokes they themselves contain. 人 and its compressed version 亻 contain only two strokes, so it will be near the beginning of the list. Locating it, one can see the page for the index on that radical, and one then normally passes through the lists of characters with one additional stroke, two additional strokes, etc. until one reaches the entries with seven additional strokes. If the chosen radical matches the radical used by the dictionary compiler (which can be difficult to guarantee for more complicated characters), and if both the user and the dictionary compiler count strokes the same way (also often a problem with characters that the user is unfamiliar with), the entry will be in that list, and will appear next to an entry number or a page number where the full dictionary entry for that character can be found.

As a rule of thumb, components at the left or top of the character, or elements which surround the rest of the character, are the ones most likely to be used as radical. For example, 信 is typically indexed under the left-side component 人 instead of the right-side 言; and 套 is typically indexed under the top 大 instead of the bottom 長. There are, however, idiosyncratic differences between dictionaries, and except for simple cases, the same character cannot be assumed to be indexed the same way in two different dictionaries.

In order to further ease dictionary lookup, dictionaries sometimes list radicals both under the number of strokes used to write their canonical form and under the number of strokes used to write their variant forms. For example, 心 can be listed as a four-stroke radical but might also be listed as a three-stroke radical because it is usually written as 忄 when it forms a part of another character. This means that the dictionary user need not know that the two are etymologically identical.

It is sometimes possible to find a single character indexed under multiple radicals. For example, many dictionaries list 義 under either 羊 or 戈 (the radical of its lower part 我). Furthermore, with digital dictionaries, it is now possible to search for characters by cross-reference. Using this "multi-component method" (which can be tried out at Jim Breen's WWWJDIC Server, also here), a relatively new development enabled by computing technology, the user can select all of a character's components from a table and the computer will present a list of matching characters. This eliminates the guesswork of choosing the correct radical and calculating the correct stroke count, and cuts down searching time significantly. One can query for characters containing both 羊 and 戈, and get back only five characters (羢, 義, 儀, 羬 and 羲) to search through. The Academia Sinica’s 漢字構形資料庫 Chinese character structure database (http://www.sinica.edu.tw/~cdp/cdphanzi/) also works this way, returning only seven characters in this instance. Harbaugh's Chinese Characters dictionary[17] similarly allows searches based on any component. Some modern computer dictionaries allow the user to draw characters with a mouse, stylus or finger, ideally tolerating a degree of imperfection, thus eliminating the problem of radical identification altogether.[f]

Though radicals are widely accepted as a method to categorize Chinese characters and to locate a certain character in a dictionary, there is no universal agreement about either the exact number of radicals, or the set of radicals. This is because radicals are merely arbitrarily chosen categories for lexicographical purposes.

The 214 Kangxi radicals act as a de facto standard, which may not be duplicated exactly in every Chinese dictionary, but which few dictionary compilers can afford to completely ignore. They serve as the basis for many computer encoding systems. Specifically, the Unicode standard's radical-stroke charts are based on the Kangxi radicals or radicals.

The count of commonly used radicals in modern abridged dictionaries is often less than 214. The Oxford Concise English–Chinese Dictionary (ISBN 0-19-596457-8), for example, has 188. A few dictionaries also introduce new radicals based on the principles first used by Xu Shen, treating groups of radicals that are used together in many different characters as a kind of radical.

In modern practice, radicals are primarily used as lexicographic tools and as learning aids when writing characters. They have become increasingly disconnected from meaning, etymology and phonetics.

Some of the radicals used in Chinese dictionaries, even in the era of Kangxi, were not genuinely distinctive graphic elements. They served only to index certain unique characters that do not have more obvious possible radicals. The radical 鬯 (chàng "sacrificial wine") is used to index only one character: 鬱 (yù, "luxuriant", "dense", or "moody"). Modern dictionaries tend to eliminate these kinds of radicals when it is possible to find some more widely used alternative graphic element under which a character can be categorized. In addition, in some modern dictionaries, characters may even be indexed under more than one radical in order to make it easier to find them.

The inflected words of European languages are decomposed into radical and termination. The radical gives the meaning; the termination indicates case, time, mood. The first sinologists applied those grammatical terms belonging to inflected languages, to the Chinese language which is not an inflected one.[2]

^Wieger uses the terms "keys of the dictionary" and "the 214 keys of K'ang-hsi" for 部首 bùshǒu, reserving the term "radical" for any element bearing meaning.[2]

It is important to note that the concepts of semantic element and "section heading" (部首 bùshǒu) are different, and should be clearly distinguished. The semantic element is parallel to the phonetic element in terms of the phonetic compound, while the section heading is a terminology of Chinese lexicography, which is a generic heading for the characters arranged in each section of a dictionary according to the system established by Xu Shen. It is the "head" of a section, assigned for convenience only. Thus, a section heading is usually the element common to all characters belonging to the same section. (Cf. L. Wang, 1962:1.151). The semantic elements of phonetic compounds were usually also used as section headings. However, characters in the same section are not necessarily all phonetic compounds. ...In some sections, such as 品 pin3 "the masses" (S. Xu 1963:48) and 爪 zhua3 "a hand" (S. Xu 1963:63), no phonetic compound is incorporated. In other words, the section heading was not commonly used as a semantic element...To sum up, the selection of a section heading is to some extent arbitrary.[11]

^When an etymon (original "root" form of a graph, such as 采 cǎi "to pick", in 採 cǎi "to pick") is analyzed alongside the remaining element(s), it cannot be said to be playing only a phonetic role. For instance, operating under the two misconceptions that a) all characters have exactly one semantic and one phonetic part, and b) each part can only play one role, many would mistakenly dissect 採 as comprising 扌 shǒu "hand" semantic and 采 cǎi phonetic. However, being the original graph, it must necessarily impart its original semantic meaning (showing as it does a hand picking from a tree) as well as its sound. In the case of 陷 xiàn "pit trap; fall into", for instance, Duan Yucai notes in his annotation of Shuowen Jiezi (v.14, p.732) that the Dà Xú 大徐 edition acknowledges that 臽 plays the dual roles of phonetic and semantic in 陷, stating "从阝, 从臽 , 臽 亦聲".

Qiu, Xigui (2000), Chinese writing, trans. by Gilbert L. Mattos and Jerry Norman, Berkeley: Society for the Study of Early China and The Institute of East Asian Studies, University of California, ISBN978-1-55729-071-7. (English translation of Wénzìxué Gàiyào 文字學概要, Shangwu, 1988.)

Xu ShenShuōwén Jǐezì (說文解字), is most often accessed in annotated versions, the most famous of which is Duan Yucai (1815). 說文解字注 Shuōwén Jǐezì Zhù (commentary on the Shuōwén Jíezì), compiled 1776–1807, and still reproduced in facsimile by various publishers. The reproduction by 天工書局 Tiāngōng Books (1998) in Taibei is useful because the seal characters are highlighted in red ink.